It is referred to someone who takes a contrary position for the sake of testing an argument, or just to be perverse. The term was introduced in the 18th century from the Medieval Latin expression 'advocatus diaboli', which suggests someone being mischievous and contradictory, being contrary for the sake of it. There are various mentions in Vatican records dating from the early 1,500s of an informal role called 'Diaboli Advocatus'. The current form of the expression was used in print in the 1760 humorous text impostors.